User:Riccardo Guida/Proposed/Quantum chromodynamics

Quantum chromodynamics is believed to represent the microscopic theory that should explain the structure and the spectrum of hadrons and plethora of strong interaction phenomena.

Quantum chromodynamics (QCD) is based on the concept of color charge - the 3-valued quantum number carried by quarks - the fundamental constituents of hadrons (mesons and baryons).
A heuristic principle of local gauge invariance with respect to color rotations determines in a unique way the Lagrangian of the theory that contains interacting quark and gluon fields. This is a renormalizable local quantum field theory whose coupling measuring the interaction strength exhibits an anti-intuitive behavior known as asymptotic freedom. Namely, the running coupling decreases logarithmically at small distances while it seems to increase in a catastrophic manner when the distance between colored objects reaches about 1 fermi (\(10^{-15} m\)).